On Wed, Jan 19, 2022 at 11:12:10PM -0800, Eric Biggers wrote: > > Given the above, as far as I know the only remaining objection to this > patchset would be that DIO constraints aren't sufficiently discoverable > by userspace. Now, to put this in context, this is a longstanding issue > with all Linux filesystems, except XFS which has XFS_IOC_DIOINFO. It's > not specific to this feature, and it doesn't actually seem to be too > important in practice; many other filesystem features place constraints > on DIO, and f2fs even *only* allows fully FS block size aligned DIO. > (And for better or worse, many systems using fscrypt already have > out-of-tree patches that enable DIO support, and people don't seem to > have trouble with the FS block size alignment requirement.) It might make sense to use this as an opportunity to implement XFS_IOC_DIOINFO for ext4 and f2fs. > I plan to propose a new generic ioctl to address the issue of DIO > constraints being insufficiently discoverable. But until then, I'm > wondering if people are willing to consider this patchset again, or > whether it is considered blocked by this issue alone. (And if this > patchset is still unacceptable, would it be acceptable with f2fs support > only, given that f2fs *already* only allows FS block size aligned DIO?) I think the patchset looks fine, but I'd really love to have a way for the alignment restrictions to be discoverable from the start.
